In the prior art relating to infra-red generation and burners designed therefor, particularly in those types of burners which involve the use of a fibrous refractory felt burner face which is permeable to a combustible mixture, a number of problems have arisen which are sufficiently important to justify modification of the burners, and in this respect the patents of one of the inventors hereof, namely the Bratko U.S. Pat. Nos. 3,824,064 and 3,785,763 have not contemplated the problem herein, which is that of confining the heat from infra-red generation to the surface and prevent its spreading outside the edges of the burners, with the consequent possibility that ignition of escaping gases could take place and heat the bodies of the burners in such a manner to adversely affect the operation thereof.
The prior patent of Smith, U.S. Pat. No. 4,035,132, is directed to the general problem herein under consideration, namely that of confining the heat and infra-red generation to the face of the burner and preventing undesired heating of certain hold-down angles but is not satisfactory from the standpoint that a line of definition is created around the perimeter of the burner face, which decreases the area of infra-red generation, and is in some cases not clearly enough defined so as to anticipate the problems which might otherwise be resolved by the construction. It is desired that complete generation over the entire face of the burner be effected so that the area of the burner may be used completely and advantageously for application to the object or material toward which the radiation is directed. In the said Smith patent, the periphery or perimeter of the burner face, is arranged to have a non-combustible mixture forced therethrough and around a hold-down or mounting angle and to cool the same there is wide variation in extent of reduction of the face generation. Consequently arrangement of burners of this nature side by side, may often cause problems in the infra-red generation so that a continuous area of the elements or members to which the radiation is directed is not covered thereby.
Other problems involved in the construction of burners of the Smith type are overcome and anticipated by the construction herein to be described and set forth in the claims appended to this disclosure.
It is a principle object of this invention therefore to provide an infra-red burner, in which the face thereof is entirely devoted to the generation of infra-red radiation, and the edges of the burner are so aranged that heat spill-over will not adversely affect the body of the burner, the construction being such that clear lines of definition of radiation are developed.
A further object of the invention is to provide construction of a burner in which a provision is made for the delivery of air in a sort of curtain around the periphery of the burner in such a manner to confine the heat spill-over, or at most minimum spill-over will not affect the burner body itself because of the use of non-combustible medium passing outwardly along said periphery.
A further object of the invention is to provide an infra-red burner of the class described, in which plenum construction is furnished to facilitate the direction of a non-combustible mixture around the periphery of a burner face, eliminate hold-down means on the surface of the matrix and enable arrangement of a series of burners closely positioned adjacent one another with no adverse affects from wide spacing of edges and thus gaps in infra-red generation.